Rules for Using System Tables

This section describes rules, restrictions, and usage information for system tables.

Note: By default, a column is defined as NOT NULL. Nullable columns are described using the “null” keyword, and are listed in the column descriptions for the tables in this book.

Permissions on System Tables
Permissions for use of the system tables can be controlled by the Database Owner, just like permissions on any other tables.
Locking Schemes Used for System Tables
In the allpages locking scheme in SAP ASE, locks are acquired on data and index pages.
Reserved Columns
The word “reserved” in the column description means that the column is not currently used by the SAP ASE server.
Updating System Tables
Direct updates on system tables are not allowed—even for the Database Owner. Instead, SAP ASE includes system procedures that you should use to make any normally needed updates and additions to system tables.
Triggers on System Tables
You cannot create triggers on system tables. If you try to create a trigger on a system table, the SAP ASE server returns an error message and cancels the trigger.

Parent topic: System Tables